Current methods of energy production have significant drawbacks, including generation of pollution which has a significant impact on the environment. Hydrogen is a promising source of clean energy and there have been numerous recent efforts to develop technologies for generating and storing hydrogen.
Town gas, the product of crude forms of coal gasification, provided fuel to light city streets prior to the development of natural gas transmission and centralized electricity. With the advent of the Hydrogen Fuel Initiative, modern coal gasification is one route for centralized hydrogen production that builds from existing coal-fired power plant infrastructure. Modern coal-fired power plants rely on burning coal in air; changing the reaction temperature and introducing water shifts the chemical reaction to produce up to 40% hydrogen. Coal gasification is one of the most economical routes to hydrogen production, and is more energy efficient than current methods that utilize the vast coal resources in the United States to make electricity. Cost estimates for hydrogen production from coal are based on “to the gate” delivery, as hydrogen storage is the subject of extensive research and development. Solid-state hydrogen storage materials under investigation include metal hydrides, chemical hydrides, and nanoporous high-surface area materials. Solid state storage goals—including gravimetric and volumetric capacity, operating temperature and pressure, and recharge and discharge rates—directly tie to the thermodynamics and kinetics of the interaction between hydrogen and the candidate material. The challenge is to obtain the desired capacities in the target temperature range while maintaining reversible hydrogen uptake and discharge. Meeting one target often compromises another: for example, polyethylene (CH2)n contains 14.3% by weight hydrogen, but hydrogen is not released in the target temperature region between −40° C. and 85° C. due to the large C—H bond strength.
Thus, there is a continuing need for methods and compositions for hydrogen generation, reversible hydrogen storage and hydrogen delivery from storage materials. Particularly desired are methods and compositions for combined hydrogen generation and reversible hydrogen storage achieved at moderate temperatures and pressures.